Method of making elastic yarn



Nov. 25, 1941. A. COTE METHOD OF MAKING ELASTIC YARN Filed NOV. 19, 1940 INVENTOR. Ari aw 6025a ATTORNEY Patented 'Nov. 1941 METHOD OF MAKING ELASTIC YARN Arthur Cot, Outremont, Quebec, Canada, assignor to United States Rubber Company, New

York, N. Y., a corporation of New Jersey Application November 19, 1940, Serial No. 366,221

7 Claims.

This invention relates to a method of making a balanced elastic yarn comprising a rubber core having a roving cover or yarn cover placed about the core by a twisting or spinning operation.

"It has been proposed heretofore to make an elastic yarn or covered rubber-thread having one or more covers laid helically about the core by a winding operation in which the package of covering yarn is revolved about the rubber core as an axis to thereby wind the textile yarn about the rubber core. {These core covering machines work very well but have to be specially constructed for this use, and when large quantities of elastic yarn are to be produced the aggregate cost of the many covering machines required to make such elastic yarn may run into a large sum of money.

Foster patent whereby excellent elastic yarn ,which is well covered and having any desired stretch up to 400% or higher may be produced upon twisting or spinning mechanism.

The present invention therefore contemplates a method of making elastic yarn by a twisting or spinning operation in contrast to the winding operation just described, whereby the use of a core covering machine may be avoided and apparatus closely resembling the twisting or spinning mechanism of the textile art may be used to produce the desired elastic yarn.

It has been proposed heretofore as disclosed by the Foster Patent No. 21,024,156, Elastic yarn and process at, making the same, to employ twisting or spinning mechanism to producea single cover elastic yarn consisting of a pretwisted rubber core having a roving cover spun about the core in a direction opposite to, the twist of the core to thereby provide a balanced single cover elastic yarn.

In accordance with the disclosure of this Foster patent the pre-twisted rubber core and the textile covering material are passed between the same pair of feed rolls,,to be delivered by these rolls to the twisting or spinning mechanism which serves to place the covering material about the core in helical windings.

Large quantities of highly satisfactorily elastic yarn having a stretch below 200% have been produced under this Foster patent, but it is found that the arrangement shown in the patent is not well adapted to produce a long stretch elastic "yarn having a stretch considerably in excess of 200%. This is due to the fact that when the pre-twisted rubber core and textile covering material are supplied to the twisting or spinning mechanism by the same pair of feed rolls, both the cover and core are necessarily advanced by these rolls at the same speed. When this arrangement is used it is not possible to feed the covering mat'erialfast enough with respect to the rubber core to provide a sufficient length of covering material to form a long stretch elastic yarn.

The present invention therefore contemplates an important improvement inthe method of the The method of the present invention is based largely upon the discovery that important advantages are obtained, and a much greater control over the stretch characteristics and other properties of the elastic yarn being produced are secured if the pretwisted rubber core and covering material are advanced toward the twisting mechanism by independent means, so that one may be advanced at a faster speed than the other. By feeding the covering material to the covering point at a diiferent speed from that of the rubber c'ore suflicient'covering material can be supplied to the rubber core to provide for any desired range of stretch.

One field in which large quantities of elastic yarn or covered rubber thread are used is that of knitting in which it is used as the yarn that is knitted into the fabric, and also as the yarn which is laid-in along the courses of the fabric.

Elastic yarn which is knitted into a fabric usually has a stretch below 200%, whereas laidin elastic yarn usually has a stretch considerably in excess of 200%. There are also other fields in which a long stretch elastic yarn is required.

Prior to the present invention it was not possible to make good elastic yarn by a spinning or twisting operation having a stretch long enough to cause it to be well adaptedfor use as a laidin elastic yarn in a knitted fabric. Through the present invention elastic yarn can be made by a spinning operation with sufiicient stretch for use in this laid-in field and in various other much greater range of stretch can be secured than could be obtained heretofore when elastic yarn was produced by a twisting or spinning operation.

In carrying out the present invention the pretwisted rubber thread is advanced to the twisting or spinning mechanism from one source of supply and the covering material is advanced to this mechanism from a separate source of supply. In some cases it may be desirable to use one pair of power driven feed rolls to ad- Vance the rubber core to the spinning position -'produced upon the apparatus of .duced 119 1 the apparatus, of Fig. 3.

ligated rubber core I. is rubber coreimay be any suitableelastic thread quired properties, and it preferably has a high and a separate and independently operated of power driven rolls for advancing the covering material to the spinning position. In other cases it will be suflicient to provide only one pair of power driven feed rolls which may be employed,

for-example, to pull the covering material towards the spinning apparatus at a predetermined speed while the rubber core may be pulled direct from its source of supply by the spinning spindle. The essential i'equirement is that provision be made for supplying-the covering material to the spinning position at a higher linear speed than the rubber core. or at a lower linear speed than the rubber core, as may be required by the particular elastic yarn being produced.-

.' above direction in which its travels so that it leaves the rolls l9 as an unztwisted or slightly twisted strand of loosely aggregated fibers.

The advancing rubber thread Ill and drafted roving I converge towards each other to a ,meeting point somewhat near the pigtail disposed and in axial alignment with the spinning spindle 2|. At this meeting point the rubber thread It and textile strand ii are brought into side by side longitudinal relation with each other and are then immediately united by a yarn plying operation imparted thereto by the spindle 2|.

- The united rubber thread and roving then pass .The above and other-features of the invention will be further understood from the following description when read in connection with the accompanying drawing illustrating goodpractical forms of mechanism for carrying out the present method. I

In the drawing:

Fig. l is a conventional diasl'ammaticwiew of one form'of mechanism for delivering a drafted roving to spinning mechanism adapted to spin the roving about a pre-twisted rubber thread to form an elastic yarn.

the core, to thereby provide an elastic yarn in Fig. 2 is a somewhat similar view of mechanism for producing an elastic yarn-having a textile yarn applied helically about the rubber core as a cover. a

Fig. 3 differs fromthe construction ofFlg. 2

onlyin that the cover is formed of two textile yarns in Fig. 3 and 01 one textile-yarn in Fig. 2. Fig.4 is anenlarged view of an. elastic yarn Fig. '1. 1

Fig. 5 is a'sim'ilar view of an elastic yarn pro-- duced upon the apparatus of Fig. 2, and

Fig. 8 is a similar-view of an-elastic yarn pro- Varlous forms of apparatusmay be employed r to carry out the method of the present invention, and while diiferent types. of twisting or spinning mechanism may be used to twist the covering material and'rubber core together, to thereby produce the elastic yarn, it is preferred .to employ the well known .type of ring and traveller spinning mechanism.

core and cover an opportunity to pass upwardly beyond the pistail 20 so as to impart a few twists In the apparatus shown-in Fig. l the 'pre conveniently supplied to spinning mechanism from a spool II. This formed of rubber or rubber like material-having desired durability and other retwist imparted thereto before it is' wound on to the package II. This rubber thread may be as 7 line as .01" indiameter or floor. or as large as d ired.

It isiiesirable to controlthe rate at which the .downwardly through the traveler 22 upon the ring 23 and inwardly-to be wound about the spindle 2| to form the package 26 or elastic yarn.

The spinning spindle 2| may be driven by the belt 25 or by other means as desired.

' -If a balanced elastic yarn is'to be produced as herein contemplated it is important that the spindle 2| be rotatedin a-direction to remove part of the twist previously imparted to the rubber' thread It, so that the operation of spinning the cover about the rubber core will serve toremove part of the twist previously imparted to which thel helical windings of the cover in one direction serve to balance the' twist of the core in the opposite direction as will be apparent fro'mFig. 4.

The speed at which the-rolls l9 are operated will determine the speed at which the covering material I5 is delivered to the covering point, and a pairof power driven feed rolls 26 mfy be provided to deliver the rubber thread It to the covering point at a speed either faster or slower than that at which the coveringmaterial is de livered, depending upon the requirements of the elastic yarn being produced.

In the construction of Fig. 1 in which a roving is employed as the covering material it is desirable that the rubber thread and covering material shall converge towards each other at substantially equal angles as shown. This will give some of the twist imparted to the combined per inch to the drafted roving and thereby increase its strength before it reaches the rubber thread in. In this manner an elastic yarn havinga stronger .roving cover as well as a greater I stretch than heretofore may be produced.

rubberthread II is unwound from the spool 1 This is readily accomplished by supporting the and so that-it rest by gravity upon the power driven roll II to thereby rotate the spool so asto unwind the rubber thread ;there-' from at a uniform speed irrespective of the size of the package. The arms. ll pivoted at I may be provided to support the spool II in engagement with the roll l2.

The covering material shown in 1 com- Q prises the roving l5 Supplied by. the'bobbin- I.'

This roving is prefera y r fted in a well known manner by the pairs of drafting rolls I1, is and It which serve to attenuate the roving in the In some casesit may be desirable to produce an elastic yarn having a cover of textile yarn in place'of the roving of Figs. 1 and 4. In this case the'apparatus of Fig. 2 may be employed wherein the same type of spinning mechanism of Fig. 1 is; provided and the .pre-twisted rubber thread i 9' maybe supplied from a let-on package ii the same as in Fig. 1. In this construction 01 Fig. 2

the textile yarn 2'! forming the cover for the elastic yarn may be supplied from a cone 28. As this yarn 21 leaves its supply cone it preferably is drawn through a tension device 29 adapted to exert a slight tension thereupon, and is preferably pulledforward by the power driven feed rolls '30 to pass downwardly to the pigtail 26.

In the construction of Fig. 2 it should be noted that the feed rolls 2! of Fig. 1 have been omitted. This is because it is found that the feed rolls 28 are not necessary since the tension of the rubber thread and rate of feed of the same can be controlled simply by employing the driving roll i2 to control the speed at which the rubber thread IO isllllWOliIid {from its package II. It

apparent that by varying the speed of rotation of the feed rolls 30 relative to the speed or rotation of the feed roll II, the textile yarn 27 may be supplied to the rubber thread as fast or as slow as desired to thereby produce an elastic yarn having any desired stretch. The covering yarn 21 as will be apparent from Fig. is disposed helically about the twisted rubber core in a direction to balance the twist or the rubber core and thereby produce a balanced elastic yarn.

The apparatus of Fig. 3 is the same as that shown in Fig. 2 except means is provided for supplying two textile yarns 3| and 32 to the rubber thread ill" in place of the single textile yarn 21 of Fig. 2. This produces the elastic yarn shown in Fig. 6 having two helically wound yarns disposed side by side upon the rubbercore in place or the single yarn of Fig. 5. The constructions shown in Figs. 5 and 6 are particularly well adapted for use in a long stretch elastic yarn.

The covering material used in Fig. 1 may be a roving of cotton, wool, non-continuous lengths of rayon or silk, or a roving of other textile fibers. The covering material of Figs. 2 and 3 may be cotton, wool, silk, rayon, Nylon or any other yarn. In some of the claims the words "textile strand have been used to include the roving of Fig. l and also the yarn of Figs. 2 and 3.

It will be apparent from the foregoing that by employing the present method it is possible to use well known textile twisting or spinning machines to produce an elastic yarn having any desired range of stretch from say 40% up to 400% or higher, and accurately to control the disposition of the cover upon the core during the spinning operation. It is also possible to make a long stretch elastic yarn without subjecting the rubber thread to a high tension while the cover is being applied thereto and thereby avoid frequent thread breakage during the covering operation.

The present method provides greater leeway in making elastic yarn than is secured when the winding type of core covering machine above referred to is employed, since in the core covering machine the weight of the travelers is dependent upon largely to control the disposition of the cover about the core, whereas by employing the present method the disposition of the cover about the core is controlled primarily by the relative speed at which the core and cover are supplied to the spinning point. As a result in the present method it is not necessary to vary to any substantial extent the weight of the travelers used for different elastic yarns.

The following examples are given as showing a few of the elastic yarns that have been, produced by the method of the present invention.

TABLE I.--Yarn covered elastic yarn A B c l Corc-rubber thread. 100's) 100's 100's. 2 Cover Zl/l/l cotton. 22/1/1 cotton. 22/1/1 cotton. 3 Elongation-elastic 200% 280 400%. yarn. 4 Yards per pound--- 38m 3640 .L 2740.

elastic yarn normal condition. 5 Length of (relaxed) 25.2" 26.5" 36.

coreinlyard. 0 Lengtgioicoverinl 124.7" 158.0" 207.9".

yar 7 Bare core-by 27.3% 26.0 25.0.

weig t. 8 Coven-by weight 72.7% 74.0 75.0. 9 Gauge-elasticyern .019 .0226 .027.

relaxed.

TABLE II.-Roomg covered elastzc yarn A B C 1 Core-rubber thread l00'sl00s l00s. 2 Cover-roving 4 bank 2 4 hank 3 4 bank 3 ends cotends cotends cotto ton. 3 Elongation-elastic yarn 220% 330% 4 Yards per pound-elastic 3150 yarn normal condition. 5 Length of (relaxed) core 39.6"

in 1 yard. 8 Length of cover in 1 yard 93 204.0 7 Bare core-by weight... 30.0. 8 Cover-by weight 70.0. 9 Gauge-elastic yarn re- .028.

laxed.

Theoretical length.

The large excess in the length of cover relative to the length of core in the above tables is readily secured by feeding the cover to the twisting mechanism faster than the core as. herein contemplated.

,Having thus described my invention, what I claim and desire to protect by Letters Patent is:

l. The method of making a balanced single cover elastic yarn which consists in delivering a pre-twisted rubber thread and a covering yarn along separate paths and at independently controlled speeds to a meeting point adjacent twisting mechanism, to thereby bring the rubber thread and a predetermined different length of said yarn into side by side longitudinal relation, and then twist them together by a yarn plying operation in a direction to remove part of the twist previously imparted to the rubber thread and place one about the other so that as the thread assumes a central position the yarn will be helically about the rubber thread as a cover.

2. The method of making a-balanced single cover elastic yarn whic consists in delivering a pre-twisted rubber thread and a textile strand along separate paths and at independently controlled speeds to a meeting point adjacent twisting mechanism, to thereby bring the rubber thread and a predetermined different length of said strand into side by side longitudinal relation, and then twist them together by a yarn plying operation in a direction to remove part of the twist previously imparted to the rubber threadand place one about the other so that as the thread assumes a central position the strand will lie helically about the rubber thread as a cover.

3. The method of making a balanced single cover elastic yarn which consists in supporting in feeding relation to twisting mechanism a source of textile covering yarn and a pre-twisted rubber thread, exerting an independently operated pulling force on the textile yarn and thread to advance them at independentspeeds towards a meeting point, bringing them together into side by side longitudinal relation, and then twisting them together by a yarn plying operation in a direction to remove part or the twist previouslyimparted to the rubber, thread and. piaemr about the other so that as the thread assumes central position the strand will lie helically about the rubber thread as a cover that balances the twist of the thread.

4. The method of making a substantially balanced single cover elastic yarn which consists in supporting in feeding relation to twisting mechanism a source of textile covering'strand and a pre-twisted rubber thread, operating the twisting mechanism to exert an advancing pull on the strand and thread, exerting a further advancing pull upon said strand independently of said thread to thereby advance the strand faster than the thread and bring them into side by side longitudinal relation, and then twist them together by a yarn plying operation in the opposite direction to the twist previously imparted to the rubber thread to place one about the other so that as the thread assumes a central position the strand will lie helically about the rubber thread as a cover.

5. The method of making a substantially balanced single cover elastic yarn which consists in supporting in feeding relation to twisting mechanism a source of textile covering strand and a pre-twisted rubber thread, exerting an advancing pull on the strand and exerting a separate and independent advancing pull on the thread to advance one faster than the other, bringing them together into side by side longitudinal relation and twisting them together by a yarn plying operation in the opposite direction to the twist previously imparted to the rubber thread to place one about the other so that as the thread assumes a central position the stand will lie helically about the rubber thread as a cover.

6. The method of making a substantially balanced single cover elastic yarn which consists in supporting in feeding relation to twisting mechanism a source of textile covering strand and a pre-twisted rubber thread, providing separate and independent power driven feed means for the thread and strand operable to advance the thread and strand at different relative speeds towards a meeting point, bringing them together into side by side longitudinal relation, and then x twisting them together by a yarn plying operation in a direction to remove part of the twist previously imparted to the rubber thread and place one about the other so that as the thread assumes a central position the yarn will lie helically about the thread as a cover.

7. The method of making a balanced single cover elastic yarn which consists in supporting in feeding relation to twisting mechanism a. plurality of packages of textile yarn and a supply of pre-twisted rubber thread, exerting an advancing pull on each yarn and exerting a separate and independent advancing pull on the rubber thread to advance one faster than the other, bringing them together into side by side longitudinal relation, and then twisting them together by a yarn plying operation in the opposite direction to the twist previously imparted to the rubber thread to thereby decrease the twist of the rubber thread and place one about the other so that as the thread assumes a central position the yarns will lie helically about the thread so as to balance its twist and hold the thread stretched.

ARTHUR COTE. 

